This invention relates to refrigerant compositions for cooling and heating applications, and specifically relates to ternary and higher blends of halocarbons.
Concern over the ozone depletion potential of certain halocarbons has resulted in a search for alternative compounds having lower ozone depletion potentials. Dichlorodifluoromethane is the most widely used refrigerant and is expected to be subject to reduced usage because of its high ozone depletion potential.
In refrigeration applications, and more specifically in automobile air conditioning systems, refrigerant is often lost through leaks during operation, such as through shaft seals, hose connections and solder joints. In addition, refrigerant may be released to the atmosphere during maintenance procedures performed on refrigeration equipment.
Most commercial refrigerants which are now used are pure fluids or azeotropes; many of these refrigerants have ozone depletion potential when released to the atmosphere. Some nonazeotropic mixtures of refrigerants may also be used but they have the disadvantage of changing composition when a portion of the refrigerant charge is leaked or discharged to the atmosphere. Should these mixtures contain a flammable component, they could also become flammable due to the change in composition which occurs during the leakage of vapor from refrigeration equipment. Refrigeration equipment operation could also be adversely affected due to this change in composition and vapor pressure which results from fractionation.
What is needed, therefore, are substitute refrigerants which maintain important refrigerant properties of vapor pressure and nonflammability over a wide range of compositions, while also having reduced ozone depletion potential.